Lubrication of Rough Surfaces by a Boundary Film-Forming Viscosity Modifier Additive

In previous work it was shown that some functionalized polymers used as viscosity index improvers are able to form thick boundary lubricating films. This behavior results from adsorption of the polymer on metal surfaces to form a layer of enhanced viscosity adjacent to the surface. In the current work the behavior of one such polymer in rough surface contact conditions is studied, using both model and real rough surfaces. It is found that the polymer is able to form a thick boundary film in rough surface contact, just as it does with smooth surfaces. It is also shown that the effect of this boundary film is to significantly reduce friction in rolling-sliding, rough surface, lubricated contact.

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The Application of Ultrasonic NDT Techniques in Tribology

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1243/135065005x9763 ◽

2005 ◽

Vol 219 (5) ◽

pp. 347-366 ◽

Cited By ~ 23

Author(s):

R. S. Dwyer-Joyce

Keyword(s):

Rough Surface ◽

Ultrasonic Waves ◽

Current State ◽

Surface Contact ◽

Machine Elements ◽

Lubricated Contact ◽

Rough Surface Contact ◽

Ultrasonic Ndt

The use of ultrasonic reflection is emerging as a technique for studying tribological contacts. Ultrasonic waves can be transmitted non-destructively through machine components and their behaviour at an interface describes the characteristics of that contact. This paper is a review of the current state of understanding of the mechanisms of ultrasonic reflection at interfaces, and how this has been used to investigate the processes of dry rough surface contact and lubricated contact. The review extends to cover how ultrasound has been used to study the tribological function of certain engineering machine elements.

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A Reconstruction and Contact Analysis Method of Three-Dimensional Rough Surface Based on Ellipsoidal Asperity

Journal of Tribology ◽

10.1115/1.4045633 ◽

2020 ◽

Vol 142 (4) ◽

Cited By ~ 2

Author(s):

Yuqin Wen ◽

Jinyuan Tang ◽

Wei Zhou ◽

Lin Li

Keyword(s):

Rough Surface ◽

Rough Surfaces ◽

Minimum Mean Square Error ◽

Three Dimensional ◽

Contact Fatigue ◽

Contact Analysis ◽

Analysis Method ◽

Surface Asperity ◽

Surface Contact ◽

Rough Surface Contact

Abstract The 3D rough surface modeling and contact analysis is a difficult problem in the study of rough surface contact. In this paper, a new method for reconstruction and contact analysis of asperities on 3D rough surfaces is proposed based on real rough surfaces. Watershed algorithm is used to segment and determine the area of asperities on the rough surface. According to the principle of minimum mean square error, ellipsoid fitting is carried out on asperities. Based on the elastic-plastic contact model of a single ellipsoidal asperity, a stable and efficient method for 3D rough surface contact analysis and calculation is proposed. Compared with existing calculating methods, the present method has the following characteristics: (1) the constructed surface asperity is closer to the real asperity in contact, and the calculation of asperity parameters has better stability under different sampling intervals and (2) the contact pressure, contact area, and other contact parameters of the 3D rough surface are calculated with high accuracy and efficiency, and the calculation convergence is desirable. The reconstruction and contact analysis method of the 3D rough surface asperity proposed in this paper provides a more accurate reconstruction and calculation method for the study of contact fatigue life and wear failure of rough surfaces.

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A Comparative Study on Equivalent Modeling of Rough Surfaces Contact

Journal of Tribology ◽

10.1115/1.4039231 ◽

2018 ◽

Vol 140 (4) ◽

Cited By ~ 2

Author(s):

Xi Shi ◽

Yunwu Zou

Keyword(s):

Rough Surface ◽

Rough Surfaces ◽

Contact Analysis ◽

Contact Forces ◽

Sliding Contact ◽

Contact Model ◽

Surface Model ◽

Normal Contact ◽

Surface Contact ◽

Rough Surface Contact

Greenwood and Tripp (GT model) have proposed that the contact analysis of two rough surfaces (two-rough-surface contact model) could be considered as an equivalent rough surface in contact with a rigid flat (single-rough-surface contact model). In this paper, by virtue of finite element method, the normal contact analysis was performed with two-rough-surface contact model and its equivalent single-rough-surface contact model, and it was verified that the resultant normal contact forces are in good agreement with each other for these two models, meanwhile the equivalent stress is a little bit lower for two-rough-surface model due to shoulder-to-shoulder contact. In contrast, the sliding contact analysis was also performed with these two models, respectively, and the results show a great disparity with each other in all contact parameters due to the strong plowing effects in two-rough-surface model. Therefore, this equivalence approach proposed by Greenwood and Tripp is only valid for normal contact of rough surfaces and not valid for sliding contact.

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